KR20010083043A - Multifunctional reactive monomers for safety protection of nonaqueous electrochemical cells - Google Patents

Abstract

The present invention, (a) one or more solvents; (b) one or more ionic salts; And (c) a non-aqueous electrolyte containing a polyfunctional monomer containing two or more unsaturated aliphatic reactive shares per molecule, the polyfunctional monomer being soluble in one or more solvents, When the electrolyte is heated, it is rapidly polymerized to increase the viscosity and internal resistivity of the electrolyte. When incorporated into a non-aqueous electrolyte, the polyfunctional reactive monomer improves the safety of the current generating cell by rapidly polymerizing to increase the viscosity and internal resistivity of the electrolyte at elevated temperatures. The present invention also relates to a current generating battery containing the non-aqueous electrolyte, a manufacturing method of the non-aqueous electrolyte and a current generating battery, and a method of increasing the safety of the current generating battery.

Description

Multifunctional reactive monomers for safety protection such as non-aqueous electrochemical cells {MULTIFUNCTIONAL REACTIVE MONOMERS FOR SAFETY PROTECTION OF NONAQUEOUS ELECTROCHEMICAL CELLS}

Throughout this application, reference is made to the various publications, patents, and published patent applications by reference. The disclosures of patents, patents, and published patent applications referred to herein are incorporated herein by reference in order to more fully describe the technical level to which the present invention relates.

The current generating battery and the storage battery including the battery are composed of a pair of electrode electrodes of opposite polarity separated by an electrolyte. The charge flow between the electrodes is maintained by an ionically conducting electrolyte.

Successful use of batteries, etc., depends on their safety in operation under normal conditions and even under abuse. Inadequate usage, such as short-circuit or rapid overcharging of the battery, causes self-heating of the battery as compared to resistive heating, which causes thermal runaway. Self-heating of a storage battery becomes a problem especially when utilizing a lithium positive electrode. Lithium batteries have much higher power storage densities than lithium-based batteries, but lithium's reactivity with most materials and its melting point of only about 180 ° C enhance the potential for self-heating and thermal runaway. . This reactivity of lithium to the electrolyte and other materials of the battery is typically increased for secondary or rechargeable lithium batteries in the cycling of lithium. The main process causing self heating of secondary lithium batteries typically involves a chemical reaction between the lithium and electrolyte solvents in the cycle. These self-heating reactions are believed to start at temperatures around 100 ° C. At temperatures above 100 ° C., it is believed that further contributions to cell self-heating come from the exothermic decomposition of the electrolyte as well as from the reaction between lithium and electrolyte ionic salts.

One approach to reducing the potential of the unsafe and explosive state of lithium batteries has been to use mixtures of low reactive electrolyte solvents with lithium. For example, US Pat. No. 4,753,859 to brands and others describes the use of one or more polyethylene glycol dialkyl ethers with ethylene carbonate and propylene carbonate as electrolyte solvents to improve the safety properties of non-aqueous lithium batteries. Also, for example, Wilkinson and other US Pat. No. 5,219,684 disclose sulfolane as an electrolyte solvent for improving safety in electrochemical cells having a lithium-containing anode as an active material and a cathode having lithium-bonded manganese dioxide. And the use of glimps. Although choosing an electrolyte solvent formulation that reduces reactivity with lithium is beneficial for safety, solvent selection alone does not provide strong protection against overheating and thermal runaway. Drawbacks of this approach with less reactive electrolyte solvents, etc. While the battery does not close or decrease the current flow at high temperatures, it is still possible to achieve high energy electrochemical reactions that lead to further thermal accumulation and degradation, which could lead to an explosive state entirely. In addition, the electrolyte solvent formulation is incompatible with the particular negative electrode formulation used in the battery. During the discharge and charging of an electrochemical cell, many compounds of electrochemical reduction and oxidation are formed which cannot be stabilized or otherwise incompatible with the electrolyte solvent. For example, solid yellow earth cathodes are highly desirable for use with lithium-containing anodes due to the extreme high power density of this combination of electroactive materials, but are typically used in the discharge or reduction cycles of these dry lithium-sulfur type batteries. The organic and inorganic polysulfides formed are incompatible with one or more solvents such as ethylene carbonate in the electrolyte solvent mixture selected for safety.

Another approach to enhancing the safety of electrochemical cells is described, for example, in US Pat. No. 4,971,867 to Watanabe and US Pat. No. 5,008,181 to Johnston, which increase the electrical resistance at high temperatures thereby reducing the flow of current through the cell. A suppressive PCT (positive temperature coefficient) device was incorporated. PCT devices can provide beneficial safety protection against internal short circuits and against overheating and overdischarging conditions, but they do not fit effectively virtually closing or reducing the activity of reactive chemistry in the cell.

In order to control overheating under misuse, it has been conceived that thermally activated separators have been developed for insertion between the cathode and the anode. The microporous sheet is deformed so as to exhibit a low resistance at a normal operating temperature but cannot be reversed to a product having a high resistance at high temperatures, while maintaining its dimensional integrity, the microporous sheet may function as a heat activated separator. I have also thought. For example, Lundquist and others US Pat. No. 4,650,730 describe several layers of microporous sheets useful as battery separators having at least two layers with different transition temperatures for the formation of a substantially nonporous sheet at elevated temperatures. Doing. Microporous polymer films currently employed as separators in lithium batteries generally do not have the ability to prevent uncontrolled heating. Usually, polymer separators are under the influence of heat and thermal reactions. Lowered to one limit or another, or dimensionally unstable, they do not substantially reduce or close the activity of the cell's reactive chemistry.

For separators that function well as internal safety devices in lithium batteries, at least three of the amount having a melting point close to 100 ° C. for the low melting point component, preferably a high dimensional stability temperature above the melting point of lithium, and an increase in Celsius temperature of the water Increasing the impedance increase in the state of the state, it must have the characteristics of high frequency and closing speed, Raman and others Electorchem . Soc., 1993, 140, L51 to L53. It is difficult to achieve these properties in a single separator and they describe that it is easier to achieve all these properties by combining different separators. Particularly where the surface area of the separator required for the battery is very large, a combination of different polymer separators can be used to not only reduce the available volume of the electroactive material. By greatly increasing the cost of producing a storage battery, the specific capacity of the battery is reduced.

In order to overcome the safety disadvantages of conventional polymer films as battery separators, one approach is to dissolve at high temperatures to the polymer film so that the hot molten iron material dissolves, making the porosity of the microporous polymer film irreversible. Thermal molten iron material which interferes with the electrochemical reaction in a storage battery has been added. For example, Taskier and others, U. S. Patent No. 4,973, 532, describe a storage battery separator having a hot melt material adhered to a porous substrate in a predetermined geometric arrangement.

As a replacement for the dissolution deformation of the battery separator material that will provide safety protection, changes in temperature organics in the electrolyte formulation have been considered. For example, Dan and others, US Pat. No. 5,506,068, disclose a liquid electrolyte solution containing a solvent that polymerizes rapidly at temperatures in excess of 100 ° C. to increase the internal resistance of the cell and thereby safely terminate the operation of the cell. It is describing. This advantageous result states that it was only observed as 1,3-dioxolane as a solvent in the face of a negative electrode of manganese dioxide and an ionic salt of certain lithium bases, and that other combinations of electrolytes, solvents, and salts may produce the same results. I thought that I could think. Liger and others US Pat. No. 4,952,330 discloses organic electrolytes containing from 40 to 53 volume percent of polymerizable components of cyclic ethers, preferably 1,3-dioxolane is a cyclic ether, in a particular class of When placed at, it effectively prevents the internal short of the battery.

In addition to the temperature organic effect by the solvent of the electrolyte to provide safety protection, an electrolyte-containing additive or the like which is polymerized or dissolved to increase the internal resistivity of the battery has been used for safety protection. For example, Mao's European Patent Application No. 759,641 relates to a liquid electrolyte of a lithium positive electrode based battery with a lithium insertion compound negative electrode to protect the battery during overcharging by the polymerization of an additive at a battery voltage greater than the maximum working voltage. The addition of monomeric additives such as biphenyl or other aromatic additives is described. In addition, for example, US Pat. No. 5,534,365 to paper and others discloses inert melting in solid polymer electrolytes to dissolve at temperatures in the range of 80 ° C to 120 ° C to protect safety by increasing the impedance of the solid electrolyte. The use of dispersed particles of possible materials is described.

Another temperature organic approach to battery safety protection is to free the poisoning agent, which deactivates the battery when a certain temperature is reached. For example, U.S. Patent No. 4,075,400 to Fritz describes a capacitive battery poisoning agent of capsule coating in which the capsule coating dissolves at a predetermined melting point to provide heating and overload protection for the battery. U.S. Pat.No. 5,714,277 to Kawanamie describes an electrolyte solution or separator consisting of microcapsules containing chemicals that dissolve in the temperature range of 70-150 ° C. and are discharged when the microcapsules dissolve. The chemical may be a polymerization initiator, a compound having a hydroxyl group, an acid, a crosslinking agent, or a flame retardant. Microcapsules may optionally contain monomers, oligomers, or polymers. Huehner and elsewhere U. S. Patent No. 5,580, 680 discloses a solid electrolyte comprising at least one initiator capable of initiating the polymerization of the solvent component of the electrolyte at elevated temperatures. Microcapsules can be used to release control of the initiator to the electrolyte under appropriate conditions.

If the electrolyte is to function as an electrolyte at a specific initiation temperature, then the electrolyte experiences a rapid and irreversible deformation such as an increase in viscosity and internal resistivity, thereby reducing the electrolyte's ionic conductivity, e.g. overheating and thermal runaway. It would be advantageous for the design of accumulators, in particular the technology of secondary lithium accumulators, to prevent, for example, to provide an increased safety for the accumulator, such as to safely terminate the action of the accumulator.

This application claims the priority of US application SN 09 / 093,528 on June 8, 1998.

The present invention generally relates to the field of non-aqueous electrolytes and current generating cells. More specifically, the present invention provides a composition comprising (a) one or more solvents; (b) one or more ionic salts; And (c) a non-aqueous electrolyte composed of a polyfunctional monomer. When incorporated into the non-aqueous electrolyte, the polyfunctional poorly reactive monomer improves the safety of the current generating cell by rapidly polymerizing at an elevated temperature, thereby increasing the viscosity and internal resistivity of the electrolyte. The present invention also relates to a method for producing the non-aqueous electrolyte, the non-aqueous electrolyte and the current generating battery, and a method for increasing the safety of the current generating battery.

FIG. 1 shows the cycle vs. specific capacity for control cells and batteries containing DVETEG in the electrolyte, as described in Example 2. FIG.

2 shows 130 ° C. hot box safety test data for a control cell, as described in Example 2. FIG.

FIG. 3 shows 130 ° C. hot box safety test data for a cell with an electrolyte containing DVETEG, as described in Example 2. FIG.

Overview of the Invention

One aspect of the present invention relates to a non-aqueous electrolyte for use in a current generating battery, the electrolyte having a viscosity and an internal specific resistance, (a) one or more solvents; (b) one or more ionic salts; And (c) a polyfunctional monomer containing at least one unsaturated aliphatic reactive quotient per molecule, the polyfunctional monomer being easily soluble in the at least one solvent and being multifunctional when the electrolyte is heated to an onset temperature of at least 100 ° C. By rapidly polymerizing the monomer, the viscosity and internal specific resistance of the electrolyte are increased. This polymerization increases the viscosity and internal resistivity of the electrolyte, thereby increasing the safety of the battery. In one embodiment, in the rapid polymerization of the electrolyte at the onset temperature, the viscosity and internal resistivity of the electrolyte increase to an extent sufficient to safely terminate the current generating action of the battery.

In one embodiment, the reactive portion of the multifunctional monomer of the non-aqueous electrolyte of the present invention is vinyl (CH ₂ = CH-), allyl (CH ₂ = CH-CH _2- ), vinyl ether (CH ₂ = CH-O Allyl ether (CH ₂ = CH-CH ₂ -O-), allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), allyl amine (CH ₂ = CH-CH ₂ -NH) -), Acrylyl (CH ₂ = CH-C (O)-), acrylate (CH ₂ = CH-C (O) -O-), acrylamide (CH ₂ = CH-C (O) -NH- ), Methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), methacrylate (CH ₂ = C (CH ₃ ) -C (O) -0-), and crotoxyl (CH ₃ -CH = C (CH ₂ ) -C (O)-).

In one embodiment, the polyfunctional monomer is a vinyl ether monomer selected from the group consisting of polyfunctional vinyl ether monomers, preferably divinyl ether monomers, trivinyl ether monomers, and tetravinyl ether monomers. In a more preferred embodiment, the polyfunctional monomer is a divinyl ether monomer. In the most preferred embodiment, the divinyl ether monomers are divinyl ether of ethylene glycol, divinyl ether of diethylene glycol, divinyl ether of triethylene glycol, divinyl ether of tetraethylene glycol, 1,4-butanediol Divinyl ether and divinyl ether of 1,4-cyclohexanemethanol.

In one embodiment, the non-aqueous electrolyte of the present invention is selected from the group consisting of liquid electrolytes, gel polymer electrolytes, and solid polymer electrolytes. In a preferred embodiment, the electrolyte is a liquid electrolyte.

In one embodiment, the at least one solvent of the non-aqueous electrolyte of the present invention is N-methyl acetamide, acetonitrile, organic carbonates, sulfolanes, sulfones, N-alkyl pyrrolidones, dioxorenes And a solvent selected from the group consisting of glymes, siloxanes and xylenes.

In one embodiment, one or more ionic salts of the non-aqueous electrolyte of the present invention contain lithium salts.

In one embodiment, the weight ratio of the combined total weight of the multifunctional monomers in question to the combined total weight of one or more solvents in the non-aqueous electrolyte of the invention ranges from 0.01: 1 to 0.25: 1. In a preferred embodiment, the weight ratio is in the range of 0.02: 1 to 0.15: 1, more preferably in the range of 0.02: 1 to 0.1: 1.

In one embodiment, the non-aqueous electrolyte of the present invention also contains a monofunctional monomer having one unsaturated aliphatic reactive quotient per molecule, the monofunctional monomer can be dissolved in one solvent of the electrolyte, When heated to an onset temperature of 100 ° C. or higher, it reacts rapidly with the polyfunctional monomer. In a preferred embodiment, the monofunctional monomer is a vinyl ether selected from the group consisting of vinyl ethers of 1-butanol, vinyl ethers of 2-ethylhexanol, and vinyl ethers of cyclohexanol.

In one embodiment, the weight ratio of the combined total weight of the monofunctional monomers in question to the combined total weight of the one or more solvents and the polyfunctional monomers in question ranges from 0.005: 1 to 0.2: 1. In a preferred embodiment, the weight ratio is in the range of 0.01: 1 to 0.1: 1.

In one embodiment, the non-aqueous electrolyte of the present invention also contains a polymerization initiator that will increase the rate of polymerization of the multifunctional monomer. In a preferred embodiment, the polymerization initiator contains a cationic polymerization initiator. In a more preferred embodiment, the polymerization initiator contains lithium ions.

In one embodiment, the non-aqueous electrolyte of the present invention also contains a polymerization inhibitor that will reduce the polymerization rate of the multifunctional monomer. In a preferred embodiment, the polymerization inhibitor is a tertiary amine.

In one embodiment, the non-aqueous electrolyte of the present invention also contains a solid porous separator. In one embodiment, the solid porous separator of the solid is a porous polyolefin separator. In one embodiment, the solid porous separator contains a microporous pseudo boehmite layer. In one embodiment, the porous porous separator of the non-aqueous electrolyte does not dissolve at temperatures above 100 ° C., the lowest temperature at which polymerization of the polyfunctional monomer occurs rapidly to increase the viscosity and internal resistivity of the electrolyte.

In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the cell does not polymerize if maintained at a temperature of 60 ° C. for 72 hours. In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the cell does not polymerize if maintained at a temperature of 80 ° C. for 72 hours.

In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the cell of the invention does not polymerize rapidly at temperatures below 100 ° C. In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the cell of the invention does not polymerize rapidly at temperatures below 110 ° C. In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the battery of the invention does not polymerize rapidly at temperatures below 120 ° C. In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the battery of the invention does not polymerize rapidly at temperatures below 130 ° C. In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the battery of the invention does not rapidly polymerize at temperatures below 150 ° C. In one embodiment, the polyfunctional monomer in the non-aqueous electrolyte of the battery of the invention does not polymerize rapidly at temperatures below 170 ° C.

Another aspect of the invention relates to a method for preparing an electrolyte for use in a current generating cell, wherein the electrolyte has viscosity and internal fixed resistance, the method comprising: (a) one or more solvents; One or more ionic salts; And a portion of two or more unsaturated aliphatic reactions per molecule, soluble in one or more solvents, which polymerizes rapidly when the polyfunctional monomer is heated to an onset temperature of at least 100 ° C., thereby increasing the viscosity and internal resistivity of the electrolyte. Preparing a multifunctional polymer; (b) optionally combining said solution selected from the group consisting of solid porous separators, ion conductive polymers, and polyfunctional monomers with one unsaturated aliphatic reactive share per molecule. The polyfunctional monomer is to rapidly polymerize when the electrolyte is heated to an onset temperature of 100 ° C. or more, thereby increasing the viscosity and internal resistivity of the electrolyte and increasing the safety of the battery.

Yet another aspect of the invention relates to a current generating cell comprising (i) a negative electrode, (ii) a positive electrode, and (iii) a non-aqueous electrolyte sandwiched between the negative electrode and the positive electrode, wherein the electrolyte is viscous and internal. Has a resistivity, and (a) one or more solvents; (b) one or more ionic salts; And (c) more than one unsaturated aliphatic reactivity share per molecule, which can be dissolved in one or more solvents and rapidly polymerizes when the electrolyte is heated to an onset temperature of 100 ° C. or higher, thereby increasing the viscosity and internal resistivity of the solution. It contains a functional monomer. In the rapid polymerization of the polyfunctional monomer, the safety of the battery is increased by increasing the internal resistivity of the viscous mass of the non-aqueous electrolyte.

In one embodiment, for rapid polymerization of the electrolyte at initiation temperature, the viscosity and internal resistivity of the electrolyte is critical to a level sufficient to safely terminate the current-generating action of the cell.

In one embodiment, the current generating cell is a secondary storage battery.

In one embodiment, the negative electrode of the cell of the invention contains an electroactive transition metal chalcogenide. In another embodiment, the cathode contains an electroactive conductive polymer. In another embodiment, the cathode contains a sulfur containing material. In one embodiment, the electroactive sulfur-containing material of the cathode contains elemental sulfur. In one embodiment, the cathode contains an electroactive sulfur containing material containing disulfide groups in its oxidation state.

In one embodiment, the negative electrode of the cell of the present invention is characterized in that, in the oxidation state of the electroactive sulfur-containing material, the formula -S _m- , where m is an integer greater than or equal to 3, preferably m is from 3 to 10. And more preferably m contains an electroactive sulfur-containing material, containing a polysulfide quotient of 6 to 10 integers. In the most preferred embodiment, the electroactive sulfur containing negative electrode material is a carbon-sulfur polymer. In one embodiment, the electroactive sulfur-containing anode material comprises a carbon-sulfur polymer material having their -S _m -groups as described above covalently bonded by one or more of their terminal sulfur atoms relative to the side groups on the polymer backbone chain. ; Carbon-sulfur polymer materials having their -S _m -groups incorporated into the polymer backbone chain by covalent bonding of their terminal sulfur atoms, as described above; And a carbon-sulfur polymer selected from the group consisting of carbon-sulfur polymer materials greater than 75 weight percent sulfur in the carbon-sulfur primer material.

In one embodiment, the positive electrode of the cell contains at least one material selected from the group consisting of lithium metal, lithium-aluminum alloy, lithium-tin alloy, lithium-inserted carbon, and lithium-inserted graphite.

Yet another aspect of the present invention relates to a method of forming a current generating battery, the method comprising (i) providing a negative electrode; (Ii) to prepare an anode; In addition, (i) a step of inserting a nonaqueous electrolyte between the positive electrode and the negative electrode, the electrolyte has a viscosity and internal resistivity, (a) one or more solvents; (b) one or more ionic salts; And (c) a polyfunctional monomer containing at least two unsaturated aliphatic reactive shares per molecule, the polyfunctional monomer being soluble in one or more solvents, wherein the multifunctional monomer is heated to an onset temperature of 100 ° C. or higher. In the case of rapid polymerization, the viscosity and internal resistivity of the electrolyte are increased.

Another aspect of the invention is that (i) has viscosity and internal resistivity, (a) one or more solvents; (b) one or more ionic salts; And (c) more than one unsaturated aliphatic reactive portion per molecule, which can be dissolved in one or more solvents, and rapidly polymerizes when heated to an onset temperature of 100 ° C. or higher, thereby increasing the viscosity and internal resistivity of the electrolyte. Providing a non-aqueous electrolyte containing a multifunctional monomer; Further, (ii) a method of increasing the safety of a current generating cell, comprising the steps of integrating the electrolyte into the current generating cell by inserting the electrolyte between a negative electrode and a positive electrode. In one embodiment, in the rapid polymerization of an electrolyte at initiation temperature, the viscosity and internal resistivity of the electrolyte increase to a level sufficient to gently terminate the current-generation action of the cell.

Further preferred embodiments are described below. As will be appreciated by those skilled in the art, the features of one aspect of an embodiment of the invention may also apply to other aspects or embodiments of the invention.

(Detailed Description of the Invention)

Non-Aqueous Electrolytes

One aspect of the present invention relates to a non-aqueous electrolyte for use in a current generating battery, the electrolyte having a viscosity and internal resistance, (a) one or more solvents; (b) one or more ionic salts; And (c) a polyfunctional monomer containing at least one unsaturated aliphatic reactive quotient per molecule, the polyfunctional monomer being easily soluble in the at least one solvent and being multifunctional when the electrolyte is heated to an onset temperature of at least 100 ° C. By rapidly polymerizing the monomer, the viscosity and internal specific resistance of the electrolyte are increased. This polymerization increases the viscosity and internal resistivity of the electrolyte, thereby increasing the safety of the battery. In one embodiment, in the rapid polymerization of the electrolyte at initiation temperature, the viscosity and internal resistivity of the electrolyte increases to a level sufficient to safely terminate the current generating action of the cell.

Safety protection provided by the presence of the polymerized polyfunctional monomer in the non-aqueous electrolyte of the present invention is extensive in the case of the negative active material, the solid synthetic negative electrode, and the positive electrode of the non-aqueous electrolyte mixture in the current generating battery. Suitable for use in combination. The non-aqueous electrolyte and the like of the present invention require high energy density, such as electrolyzers, primary batteries, rechargeable batteries, fuel cells, and others, and the like, in particular to those utilizing an electroactive sulfur-containing cathode. It is particularly preferred for use.

Polyfunctional monomers

As used herein, the term "polyfunctional monomer" belongs to a molecule of low molecular weight (typically about 6000 or less) that possesses more than one unsaturated aliphatic reactive share per molecule.

As used herein, the term “polyfunctional monomer” refers to more than one atom, as part of a larger molecule, that can react with similar or different reactive shares on another molecule to form a high molecular weight product molecule. It belongs to the chemical share it contains. As used herein, the term "aliphatic reactive quotient" refers to straight or branched when the molecule is in a pure state at room temperature and contains two or more atoms which are neither cyclic nor part of the cyclic quotient of the molecule. Belongs to the reactive share. As used herein, the term "unsaturated aliphatic reactive quotient" belongs to aliphatic reactive quotients containing reactive double bonds, such as, for example, carbon-carbon double bonds or unsaturated vinyl groups in vinyl ethers.

For example, divinyl ethers, such as divinyl ethers of ethylene glycol (i.e., CH ₂ = CHOCH ₂ CH ₂ OCH = CH ₂ ), each molecule may be another vinyl ether portion of the second molecule or another form. It is an example of a polyfunctional monomer because it has _two unsaturated aliphatic reactive shares (ie -CH = CH ₂ ) which can react with the reactive quotient of to form a high molecular weight molecule. In comparison, for example, vinyl ethers such as vinyl ethers of 1-butanol, for example, can be polymerized to molecules of high molecular weight via reactive quotient, but only one unsaturated aliphatic reactive quotient that is a single vinyl quotient per molecule. Since it has a, it is not a polyfunctional monomer. In addition, for example, 1,3-dioxolane, although it can polymerize under certain conditions to form a high molecular weight molecule, 1,3-dioxolane does not have an unsaturated aliphatic reactive portion, so that acet bonds Since it superposes | polymerizes through the ring opening mechanism of the share of the cyclic function, it is not a polyfunctional monomer.

Examples of suitable unsaturated aliphatic reactive moieties include vinyl (CH ₂ = CH-), allyl (CH ₂ = CH-CH _2- ), vinyl ether (CH ₂ = CH-O-), allyl ether (CH ₂ = CH-CH). ₂ -O-), allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), allyl amine (CH ₂ = CH-CH ₂ -NH-), acrylyl (CH ₂ = CH-C (O)-), acrylate (CH ₂ = CH-C (O) -O-), acrylamide (CH ₂ = CH-C (O) -NH-), methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), methacrylate (CH ₂ = C (CH ₃ ) -C (O) -O-), and crotoxyl (CH ₃ -CH = C (CH ₂ ) -C (O )-), Including, but not limited to, shares.

Suitable polyfunctional vinyl ether monomers of the non-aqueous electrolyte of the present invention include, but are not limited to, vinyl ethers selected from the group consisting of divinyl ether monomers, trivinyl ether monomers, and tetravinyl ether monomers. In a preferred embodiment, the polyfunctional monomer is a divinyl ether monomer.

Suitable divinyl ether monomers are, for example, divinyl ethers of aliphatic diols such as divinyl ethers of alkane diols and divinyl ethers of polyoxyalkylene diols (ie polyethylene glycols and polypropylene glycols). Include, but are not limited to.

Examples of divinyl ethers of alkane diols are the formula CH ₂ = CH-O- (CH ₂ ) _n -O-CH = CH ₂ , provided that n is an integer of 2 to 12 1,2-ethanediol (ie ethylene Glycol), 1.3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1 Divinyl ethers of, 10-decanediol, 1,11-bidecanediol, and 1,12-dodecanediol.

Examples of suitable divinyl ether monomers of polyoxyalkylene diols include diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, nonaethylene glycol, decaethylene glycol and And also the formula CH ₂ ═CH—O— (CH ₂ CH ₂ O) _n —CH═CH ₂ , provided that n is an integer from 2 to 135 (ie less than about 6000 molecular weight) of the dialkylene polyalkylene glycols. Vinyl ethers, including but not limited to them.

In the most preferred embodiment, the multifunctional monomer of the non-aqueous electrolyte of the present invention is selected from the group consisting of ethylene glycol of divinyl ether, diethylene glycol of divinyl ether, triethylene glycol of divinyl ether, tetraethylene glycol of divinyl ether, It is selected from the root which consists of 1, 4- butanediol of divinyl ether, and 1, 4- cyclohexanedimethanol of divinyl ether.

The multifunctional nature of the polyfunctional monomers of the non-aqueous electrolyte of the present invention allows them to undergo cross-linking reactions during their polymerization, and typically to gel further by forming three-dimensional or network structures that do not dissolve in the non-aqueous electrolyte. Calculate solid state quickly. Unless desired to be bound on a certain principle, it is believed that crosslinking reactions of polyfunctional monomers form the viscosity of the electrolyte more rapidly than only resulting from crosslinking polymerization. This more rapid formation of viscous stabilizes neutralizing the overheating and thermal runaway of the cell and, if the rapid polymerization is chosen to be of sufficient speed and amount, to close the action of the current generating cell at the high temperature that initiated the rapid polymerization. Provide a quick response. In addition, this effective viscosity formed by the crosslinking reaction during polymerization allows a low concentration of polymerizable monomer to be utilized in the electrolyte, which in turn reduces the possibility of monomer additives interfering with the electrochemical performance and stability of the electrolyte under normal action. Let's go. Polyfunctional monomers, whether aliphatic or cyclic, do not undergo crosslinking reactions by themselves, and are good at electrochemical closure at normal temperatures at relatively low concentrations of monomers, in combination with the stability of the cell at high temperatures, and in combination with stability. It does not provide the benefits of rapid crosslinking to a more gelled or solid state, rapid viscosity formation at low concentrations of polymerized monomers, including rapid safety reactions, including functionality.

The polyfunctional monomers of the non-aqueous residue of the present invention are easily soluble in one or more solvents of the non-aqueous electrolyte of the present invention. This solubility is due to the complete dissolution or miscibility of one or more polyfunctional monomers in one or more solvents of the non-aqueous electrolyte of the present invention in a weight ratio of the polyfunctional monomers to one or more solvents in the non-aqueous electrolyte sufficient to provide the desired safety protection. Determined by

Although polyfunctional monomers, if used alone or in combination with solvents of non-aqueous pre-hexyls, may have the properties of a solvent, for purposes of weight ratio determination, as used herein, The weight is not included in the weight of the solvents. A suitable weight ratio of the combined total weight of the multifunctional monomers in question to the combined total weight of one or more solvents in the non-aqueous electrolyte of the present invention is a weight ratio in the range of 0.01: 1 to 0.25: 1, preferably 0.02: 1 to 0.15: 1 Weight ratios in the range, and more preferably the weight ratios include, but are not limited to, weight ratios in the range of 0.02: 1 to 0.1: 1. For example, a solution of 5 volume percent triethylene glycol (as multifunctional monomer) (specific gravity 1.0016 g / cm ³ ) of divinyl ether, 90 volume percent 1,2-dimethoxyethane (specific gravity 0.867 g / cm ³ ) And a solution consisting of 5 volume percent o-xylene (specific gravity 0.87 g / cm ³ ) (1,2-dimethoxyethane and o-xylline together are nonaqueous electrolyte solvents) is [(0.05) (1.006)] / [(0.90) (0.867) + (0.05) (0.87)] or 0.061 to 1, to have a weight ratio of the polyfunctional monomer to the integrated solvent.

When the weight ratio of the total gross weight of the multifunctional monomers in question to the total gross weight of the solvent in the non-aqueous electrolyte of the present invention is less than 0.01; 1, the function of the current generating cell is influenced by the amount of the polyfunctional monomer insufficient at the threshold onset temperature. Large viscous formations of crosslinks and their associations tend to result in rapid polymerization, quickly and safely controlled or terminated. When the weight ratio of the total gross weight of the multifunctional monomers in question to the total gross weight of one or more solvents in the non-aqueous electrolyte of the present invention is 0.05; 1 or more, the amount of the polyfunctional monomer safely stops thermal runaway with respect to the amount of the multifunctional monomer. Rather than safely terminate the operation of the cell, the output heat tends to be too high at the threshold onset temperature so that it may produce sufficient exothermic reactions that contribute to further thermal runaway of the cell.

In one embodiment, the multifunctional monomer of the non-aqueous electrolyte of the present invention is a polyfunctional vinyl ether monomer. Polyfunctional vinyl ether monomers, even at a low weight of 1 percent of the weight of the solvent in the electrolyte, (1) remain virtually unreactant and stable in the non-aqueous electrolyte of the present invention while at the same time discharge, charge, And does not significantly disturb the electrochemistry of the cell during storage; (2) A rapid polymerization with crosslinks is characterized by an integration which provides reactivity at temperatures above the normal operating temperature of the electrolyte of the cell, such as temperatures above 100 ° C, which lead to rapid viscosity formation and increase the internal resistivity of the electrolyte. Generally have

The polyfunctional monomer of the non-aqueous electrolyte of the present invention polymerizes rapidly when the electrolyte is heated to an onset temperature of 100 ° C. or higher, thereby increasing the viscosity and internal specific resistance of the electrolyte. The nonaqueous electrolyte of the present invention is well known to those skilled in the art for measuring the viscosity and internal resistivity (in absolute or relative conditions) of materials.

As used herein, the terms “quickly polymerize” or “quickly polymerize” refer to polymerization that is at least 50 percent complete within 10 minutes under the particular reaction conditions employed. In the state of thermal runaway of a battery, polymerization should typically continue sufficiently within seconds to increase the viscosity and internal resistivity sufficient to safely slow or stop thermal runaway.

The onset temperature is at least 100 ° C., typically from 100 ° C. to about 200 ° C. In one embodiment, the onset temperature is at least 110 ° C. In one embodiment, the onset temperature is at least 120 ° C. In one embodiment, the onset temperature is at least 130 ° C. In one embodiment, the onset temperature is at least 140 ° C. In one embodiment, the onset temperature is at least 150 ° C. In one embodiment, the onset temperature is at least 160 ° C. In one embodiment, the onset temperature is at least 170 ° C.

Although the polyfunctional monomers of the non-aqueous electrolyte of the cell of the present invention rapidly polymerize at an initiation temperature of 100 ° C. or higher, they do not polymerize to a sufficient degree at temperatures within the normal operating range of the cell such that the cell terminates or adversely affects the cell. Should not. In one embodiment, the polyfunctional monomer of the non-aqueous electrolyte of the cell of the invention does not polymerize if maintained at a temperature of 60 ° C. for 72 hours (typically less than 10 percent completion, more preferably 5 percent completion). Less than polymerization). In one embodiment, the polyfunctional monomer of the non-aqueous electrolyte of the cell of the invention does not polymerize if maintained at a temperature of 80 ° C. for 72 hours (typically less than 10 percent completion, more preferably 5 percent completion). Less than polymerization). In one embodiment, the polyfunctional monomer of the non-aqueous electrolyte of the battery of this invention does not polymerize rapidly at the temperature below 100 degreeC. In one embodiment, the polyfunctional monomers of the non-aqueous electrolyte of the battery of the invention do not polymerize rapidly at temperatures below 110 ° C. In one embodiment, the polyfunctional monomers of the non-aqueous electrolyte of the battery of the invention do not polymerize rapidly at temperatures below 120 ° C. In one embodiment, the multifunctional monomer of the non-aqueous electrolyte of the battery of the invention does not polymerize rapidly at temperatures below 130 ° C. In one embodiment, the multifunctional monomer of the non-aqueous electrolyte of the battery of the invention does not polymerize rapidly at temperatures below 150 ° C. In one embodiment, the polyfunctional monomer of the non-aqueous electrolyte of the battery of the present invention does not polymerize rapidly at temperatures below 170 ° C.

Although the cells typically operate within the ambient temperature range of -20 ° C. to 50 ° C. in the office environment and during outdoor use, they may operate at high temperatures to accommodate the normal thermoforming of the cell during storage and continuous operation, which may be at high temperatures. It requires ability. For example, depending on the particular application and the particular combination of positive electrode, electrolyte, and negative electrode material utilized for that application, the specified normal operating temperature of the current generating cell typically has an upper limit of about 60 ° C., sometimes from 60 ° C. to 100 ° C. Extends to a degree in the range. These phase temperature limits are typically for short periods of time, such as 8 hours or less, with normal operating temperatures in the range of -20 ° C to 50 ° C. Safety tests at high temperatures for batteries are typically made at 130 ° C for 60 minutes or at 150 ° C for 10 minutes. Therefore, these high temperatures above 100 ° C are such that the battery must have safety protection against thermal runaway and must control or even terminate the operation at or below these temperatures prior to thermal runaway or any other safety failure of the battery. Means the temperature.

Polyolefin separators typically used in many batteries are softly melted and inverted at temperatures ranging from about 120 ° C to about 150 ° C, depending on the particular polyolefin utilized, resulting in loss of dimensional stability. The storage battery may include a temperature organic material capable of safely controlling or even ending the operation of the battery at a certain temperature before severely losing the dimensional stability of the polyolefin separator, such as the polyfunctional monomer of the non-aqueous electrolyte of the battery of the present invention. It is desirable to have a safety mechanism.

The increase in viscosity provided by rapid polymerization of the multifunctional monomer of the present invention is such that the negative active material is at least partially present in the liquid phase of the electrolyte of the battery during cycling, such as a specially constructed porous polyolefin separator and an insoluble state of the closed separator. May not prevent contact with the lithium-based anode of this liquid cathodic active material under Particularly beneficial for improving the safety properties of batteries, such as having a negative electrode containing an electroactive sulfur containing material. Increasing the viscosity by rapid polymerization of the polyfunctional monomers of the present invention, in general, the delay in mass transfer and diffusion at the lithium / electrolyte interface has been shown to improve the battery safety characteristics of these types with liquid cathodic active materials during battery use. helpful. In addition, if the battery contains some form of lithium, such as a positive electrode active material, the melting point of the lithium-based material present in some form at the positive electrode, including after a large number of discharge-charge cycles, may lead to safety protection of the battery. Below that means the temperature that must be effective. For example, because the melting point of lithium metal is about 180 ° C., battery safety that contains lithium metal is activated to prevent the temperature of these batteries from exceeding any low temperature, such as at most 170 ° C.

In non-aqueous electrolytes, the solvent is typically flammable, especially in the presence of a lithium metal in which the solvent typically reacts rapidly at high temperatures, so that in batteries, in particular lithium-based batteries, the control of temperature organics, Even safe closing is preferably only a temperature slightly above the normal operating temperature range of the battery. In addition, because batteries are transported and used in many portable devices, they have extensive safety tests and perceptions that require high standards of safety. Thus, a quick temperature organic safety control device, such as closing, may be used at thermal temperatures or at high temperatures, for example in batteries, at temperatures slightly above the normal operating temperature of the battery, such as in the range of 100 ° C to 120 ° C. Provides beneficial protection against one failure of the safety test, under one of the other modes of battery misuse, such as a nail puncture test, which may be the cause of an increase in temperature.

Depending on the application of the battery and the particular negative electrode, anode, separator, and other materials donated to the battery, certain thresholds are disclosed for safety control or even closure of the battery by the polyfunctional monomers of the non-aqueous electrolyte of the battery of the invention. It may be desirable to have a temperature. For example, if the separator used in the battery contains polypropylene that dissolves at about 150 ° C., it has a battery that is capable of operating up to a temperature as high as 110 ° C., but any temperature in the range of 115 ° C. to 130 ° C. It is desirable to have safety control or closure of the temperature organics by the polyfunctional monomers produced in

As described herein, as well as the optional use of monofunctional monomers, polymerization initiators, and polymerization inhibitors, as well as the proper selection of their weight ratios of one or more polyfunctional monomers with one or more solvents of the non-aqueous electrolyte of the battery of the present invention. By this, safety control of the temperature and state of the accumulation and rapid temperature organic storage of the battery action at a specific starting temperature of 100 ° C. or more can be achieved. The electrolyte is exposed to the initiation of the polymerization of the polyfunctional monomer and a wide range of cell safety states, depending on the temperature and the choice of materials, which will increase in any cell, for example, due to continuous thermal runaway or exothermic effects from the polymerization. Different levels of viscosity and internal resistivity can be obtained.

For example, where the increase in temperature and organic temperature of the viscosity and internal resistivity only lowers the ionic conductivity of the electrolyte by a factor of 2, the cell can either be stopped or protected against thermal runaway and then acceptable with even reduced ion conductivity. It may also return to normal capacity with battery capacity. In addition, the battery has a good safety performance if it is continuously exposed to an elevated temperature rather than for the first time before rapid polymerization of temperature organics. If increased safety of the cell is desired, this polymerization of polyfunctional monomers, which will provide a small reduction in ion conductivity, polymerizes at least 100 ° C. or some or all of the polyfunctional monomer for rapid polymerization prior to the discharge-charge use of the cell. This can be done by heating the cell to an elevated temperature, such as up to 100 ° C., for slow polymerization. Further, for example, where the temperature organic increase of viscosity and internal resistivity lowers the ionic conductivity of the electrolyte by a factor of 1000 or more, the battery can be protected against overheating and thermal runaway, and at the same time, its current generating action is prevented. To close or terminate.

If the battery contains a separator material, the safety control or safety termination of the battery is below the temperature at which the separator misses its dimensional stability, in a way that can directly contribute to safety defects, for example, resulting in a direct short between the electrolytes. It is generally preferred to take place at a temperature of. In one embodiment, the solid porous separator of the non-aqueous electrolyte of the battery of the present invention, the rapid polymerization of the polyfunctional monomer of the non-aqueous electrolyte of the battery of the present invention increases the viscosity and internal resistivity of the electrolyte and improve the safety of the battery It does not dissolve at an onset temperature of 100 ° C. or higher, which occurs to increase.

Unlike the present invention, where polyfunctional monomers (such as polyfunctional vinyl ether monomers) are present in the non-aqueous electrolyte, the monomers remain stable during operation of the cell at normal temperatures and conditions. In order to safely control the action of the cell and to polymerize rapidly at high onset temperatures, Marques et al. US Pat. No. 5,411,819 discloses vinyl ethers, divinyl ethers, ionic compounds, oligomers or bipolar aprotic liquids, and photoinitiators. A process for preparing a solid polymer electrolyte by radiation curing of the containing mixture is described. Thus, the '819 solid polymer electrolyte contains polymers of vinyl ether and divinyl ether in the form of a solid coating and does not contain polyfunctional divinyl ether monomers that can be dissolved in the solvent of the non-aqueous electrolyte. In the presence of lithium lithium tetrafluoroborate, the polymerization of the vinyl esters in the '819 patent is described as occurring spontaneously. In addition, it is said that the polymerization process of the radiation organic in the '819 patent is accelerated by heating to a temperature of about 50 ° C.

Solvents

Examples of solvents beneficial for the non-aqueous electrolyte of the present invention include N-methyl acetimide, acetonitrile, organic carbonates, sulfolane, sulfones, N-alkyl pyrrolidones, dioxolanes glimps, Siloxanes, xylenes, and one or more solvents selected from the group consisting of the above alternative forms.

Salts

Examples of ionic electrolyte salts for use in the non-aqueous electrolyte of the present invention are MClO ₄ , MAsF ₆ , MSO ₃ CF ₃ , MSO ₃ CH ₃ , MBF ₄ , MBr, MI, MSCN, MB (phenyl) ₄ , MPF ₆ , MC (SO ₂ CF ₃ ) ₃ , MN (SO ₂ CF ₃ ) ₂ ,

And others, provided that M includes Li or Na, but is not limited thereto. Other electrolyte salts useful in the practice of the present invention are disclosed in Li and other US Pat. No. 5,538,812. Preferred ion electrolyte salts are LiSO ₃ CF ₃ (lithium triflate), and LiN (SO ₂ CF ₃ ) ₂ (lithium imide).

Monofunctional Monomers

In one embodiment, the non-aqueous electrolyte of the present invention also contains a monofunctional monomer having one unsaturated aliphatic reactive share per molecule, the monofunctional monomer being a monofunctional monomer when the electrolyte is heated to an onset temperature of at least 100 ° C. It can be dissolved in one or more solvents of an electrolyte which rapidly reacts with the polyvalent monomer. As used herein, the term “monofunctional monomer” belongs to a molecule of low molecular weight (eg, about 6000 or less) possessing only one unsaturated aliphatic reactive portion. For example, vinyl ethers such as 1-butanol (ie CH ₂ = CH-O-CH ₂ CH ₂ CH ₂ CH ₃ ), such as vinyl ethers, are branched, in only one aliphatic reactive portion, Since it has a single vinyl quotient, it is a monofunctional monomer.

As previously described herein, the monofunctional monomers do not undergo crosslinking reactions with their integrated benefits by themselves for the rapid viscosity formation and safety properties of the non-aqueous electrolyte of the invention, but the multifunctional monomer of the invention And monofunctional monomers in combination with these compounds, for example, can provide rapid control of the cell's controlled viscosity and internal resistivity at onset temperatures above 100 ° C., for example, by providing an improved combination of the safety of the non-aqueous electrolyte at the operating temperature of the cell. In this increase and rapid polymerization, it is advantageously advantageously carried out.

The monofunctional monomers used in the nonaqueous electrolyte of the present invention can be dissolved in one or more solvents of the nonaqueous electrolyte of the present invention. This solubility is, for example, 0.005: 1 to 0.2: 0.2 by weight ratio of the combined total weight of monofunctional monomers donated to the combined total weight of solvents and the multifunctional monomers donated to the non-aqueous electrolyte required to provide the necessary safety protection. 1, and preferably a non-aqueous electrolyte of the present invention in a weight ratio of the combined total weight of monofunctional monomers to the combined total weight of one or more solvents and polyfunctional monomers contributed in the range of 0.01: 1 to 0.1: 1 It is determined by the complete dissolution or miscibility of the monofunctional monomers in the solvents. For the purpose of calculating this weight ratio relative to the presence of monofunctional monomers, as used herein, the weight of the polyfunctional monomers present in the solvent is integrated with the weight of the solvents.

In a preferred embodiment, the monofunctional monomer for use in the non-aqueous electrolyte of the present invention is a monofunctional monomer selected from the group consisting of vinyl ethers and allyl ethers. In a more preferred embodiment, the monofunctional monomer is a vinyl ether selected from the group consisting of vinyl ethers of 1-butanol, vinyl ethers of 2-ethylhexanol, and vinyl ethers of cyclohexanol.

Monofunctional vinyl ether and allyl ether monomers do not substantially react with the non-aqueous electrolyte of the present invention and remain stable and do not significantly interfere with the electrochemical performance of the cell during discharge, charging, and storage at normal operating temperatures and conditions. Generally have At temperatures above the normal operating range of the electrolyte in the cell, such as 100 ° C. or higher, these monofunctional monomers crosslink the polyfunctional monomers at or above 100 ° C. or higher to contribute to rapid viscosity formation and increased internal resistivity of the electrolyte. Polymerize in reaction and integrated state.

Polymerization initiators

In one embodiment, the non-aqueous electrolyte of the present invention also contains a polymerization initiator that increases the rate of polymerization of the multifunctional monomer. Suitable initiators include free group polymerization initiators and cathodic polymerization initiators.

Examples of suitable free group polymerization initiations include, for example, acyl peroxides such as diacetyl peroxide, dibenzoyl peroxide, and dilauryl peroxide; Peresters such as tert-butylperoxy pivalade, tert-butyl peroxy-2-ethylhexanoate; Alkyl peroxides such as di-tert-butyl peroxide; For example, percarbonates such as dicyclohexyl peroxydicarbonate; And, for example, 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 1,1'-azobis (cyanocyclohexane), And percarbonates such as 2,2'-azobis (methylbutyronitrile), but are not limited thereto.

In a preferred embodiment, the polymerization initiator contains a cationic polymerization initiator. Suitable cationic polymerization initiators are hydrogen ions, such as boron, zinc. Lewis acids such as halides of aluminum, iron and tin include, but are not limited to.

In a more preferred embodiment, the polymerization initiator contains lithium ion, which is typically integrated with counter anions, which are poorly nucleophiles, or any complex with ether containing molecules such as, for example, glims. do.

The amount of free radicals and cationic polymerization initiators for use in the present invention depends on the normal operating temperature and condition of the non-aqueous electrolyte in the cell, and at high temperatures so as to safely control or terminate the onset of rapid polymerization and the action of the cell. Depending on the temperature threshold for the rate of polymerization, it may be varied widely. Generally about 0.1 to 5.0% of polymerization initiator is used based on the combined total weight of the polyfunctional and monofunctional monomers donated to the non-aqueous electrolyte.

Polymerization inhibitors

In one embodiment, the non-aqueous electrolyte of the present invention further contains a polymerization inhibitor that will reduce the polymerization rate of the multifunctional monomer.

In a preferred embodiment, the polymerization inhibitor contains tertiary amines. Examples of suitable tertiary amines include, but are not limited to, triethylamine, tripropylamine, tributylamine, tribenzylamine, trioctylamine, triphenylamine, and methylpiperidine.

The amount of polymerization inhibitors for use in the present invention depends on the temperature threshold for the rate of polymerization required at high temperatures for the onset of rapid neutralization and for the safe action of the cell, depending on the normal operating temperature and condition of the non-aqueous electrolyte in the cell. It can be changed extensively. Generally about 0.05 to 5.0% of polymerization inhibitor is used based on the combined total weight of the polyfunctional and monofunctional monomers in the non-aqueous electrolyte.

State of non-aqueous electrolyte

The non-aqueous electrolyte of the present invention may be any type of non-aqueous electrolyte known in the art. In one embodiment, the non-aqueous electrolyte of the present invention is selected from the group consisting of liquid electrolytes, gel polymer electrolytes, and solid polymer electrolytes. In a preferred embodiment, the electrolyte is a liquid electrolyte.

To form the liquid electrolyte of the present invention, one or more ionic electrolyte salts are typically added to one or more electrolyte solvents and one or more polyfunctional monomers. For example, other optional additives such as monofunctional monomers, polymerization initiators, and polymerization inhibitors may also be added.

To form the gel polymer electrolyte of the present invention, at least one ion conducting polymer is typically added to at least one electrolyte solvent, at least one ion electrolyte salt, and at least one polyfunctional monomer. The amounts of electrolyte solvents and polyfunctional monomers differ markedly from the solid polymer electrolyte in the solid state and end up in an electrolyte in the gel or semisolid state.

Examples of suitable ion-conducting polymers are polyethylene oxides (PEO), polypropylene oxides, polyacrylonitriles (PAN), polysiloxanes, polyimides, polyethers, sulfonated polyimides, polymerized divinyl Acrylate and methacrylate polymers and copolymers such as polyethylene glycols, polymerized polyethylene glycol-bis- (methyl acrylates) and polymerized polyethylene glycol-bis- (methyl methacrylates), derivatives thereof, Including, but not limited to, those copolymers described above and those selected from the group consisting of crosslinked and networked structures.

To form the solid polymer electrolyte of the present invention, one or more ionic conducting polymers are added to one or more solvents (typically less than 20 weight percent of the total weight of the electrolyte), one or more ionic electrolyte salts, and the multifunctional monomers in question. Examples of suitable ion conducting polymers include polyethers, polyethylene oxides (PEO), polypropylene oxides, polyimides, polyphosphazenes, polypolyacrylonitriles (PAN), acrylates and methacrylates. Including those selected from the group consisting of polymers and copolymers, polysiloxanes, polyether graft polysiloxanes, derivatives of electricity, copolymers of electricity, and structures of crosslinking and reticular bonding of electricity It is not limited.

Solid porous separators

In one embodiment, the non-aqueous electrolyte of the present invention further contains a solid porous separator. Typically, the separator is a solid, non-conductive or insulating material that isolates or insulates the positive and negative electrodes from each other and, in the pores of the separator, contains one or more ionic electrolyte salts and solvents, and optionally ion conductive polymers.

Various materials are known in the art for use in porous layers or separators in current generating cells. Suitable solid porous separator materials include, but are not limited to, for example, polyolefins such as polyethylenes and polypropylenes, fiberglass filter papers, and ceramic materials. In general, these separator materials are supplied as a porous self-supporting membrane sandwiched between the positive electrode and the negative electrode in the manufacture of the current generating cell.

Instead, the porous separator layer may be applied directly to one of the electrodes, for example, as described in US Pat. No. 5,194,341 to Bagley and others. Examples of separators suitable for use in the present invention include US patent application SN 08, co-issued by Carlson and others, under the "Electrochemical Battery Separator", which may be provided as a self-supporting film or by direct coating on one electrode. Such as those containing a microporous pseudo boehmite layer as described in / 995,089. In one embodiment, the solid porous separator is a porous polyolefin separator. In one embodiment, the solid porous separator contains a microporous pseudo boehmite layer.

Non-aqueous electrolyte preparation method

Another aspect of the invention is a method of preparing a non-aqueous electrolyte for use in a current generating cell, the electrolyte having viscosity and internal resistivity, the method comprising: (a) one or more solvents; One or more ionic salts; And a polyfunctional monomer containing two or more unsaturated aliphatic reactive shares per molecule, which can be dissolved in the one or more solvents, and rapidly increases when the electrolyte is heated to an onset temperature of 100 ° C. or more, thereby increasing the viscosity and internal resistivity of the electrolyte. Preparing a solution of; (b) optionally combining the solution with another material selected from the group consisting of solid porous separators, ion conductive polymers, and monofunctional monomers having one unsaturated aliphatic reactive share per molecule. The polyfunctional monomer rapidly polymerizes when the electrolyte is heated to an onset temperature of 100 ° C. or higher, thereby increasing the viscosity and internal resistivity of the electrolyte and increasing the safety of the battery.

Current generating battery

One aspect of the present invention relates to a current generating battery comprising (i) a negative electrode, (ii) a positive electrode, and (iii) a nonaqueous electrolyte sandwiched between the negative electrode and the positive electrode, the electrolyte having viscosity and internal resistivity. (A) one or more solvents; (b) one or more ionic salts; And (c) more than one unsaturated aliphatic reactivity share per molecule, which can be dissolved in one or more solvents and rapidly polymerizes when the electrolyte is heated to an onset temperature of 100 ° C. or higher, thereby increasing the viscosity and internal resistivity of the electrolyte. It contains polyfunctional monomer to make.

In the rapid polymerization of the polyfunctional monomer, the viscosity and internal resistivity of the non-aqueous electrolyte are increased, thereby increasing the safety of the battery. In one embodiment, in the rapid polymerization of the electrolyte at the initiation temperature, the viscosity and internal resistivity of the electrolyte increases to a level sufficient to safely terminate the current generating action of the cell.

In the battery of the present invention, the polyfunctional monomer is rapidly polymerized at a certain starting temperature of 100 ° C. or higher, for example, a threshold polymerization temperature of 120 ° C., thereby increasing the viscosity of the solvent-containing portion of the non-aqueous electrolyte and maintaining the battery's function. Control or even shut it down. This increase in viscosity improves the safety characteristics of the cell by effectively delaying the mass transfer flow in the cell and increasing the internal resistivity. This gelation of the electrolyte is one that generally reduces ionic conductivity by a factor of at least 2 to 10, thus delaying mass transfer of ionic species at electrode contact, thereby generally inducing mass transfer diffusion limitations. The viscosity of this increase in the electrolyte is considered to be possible as the master of the safety closure effect of terminating the current action of the battery of the safety effect against overheating and thermal runaway, if the viscosity increase is large enough. In a preferred embodiment, the polyfunctional monomer is a polyfunctional vinyl ether monomer, as described herein.

Although the current-generating cells of the present invention can be utilized in a variety of primary and secondary storage batteries known in the art, the use of these batteries in secondary or rechargeable batteries is preferred. The advantage of the temperature organic polymerization of the polyfunctional monomers of the cell of the present invention is the progressive increase in the potential for thermal runaway and instability at which the positive and negative active materials are at temperatures above the normal operating range of the cell application and under other negative conditions. If subjected to many electrochemical reactions leading, it can be employed to help protect the secondary battery through many repeated discharge and charge cycles.

Cathodes

The polyfunctional monomers of the non-aqueous electrolytes of the present invention exist as a soluble type in the non-aqueous electrolyte, and the stability and reactivity of these polyfunctional monomers (and especially polyfunctional vinyl ether monomers) are typically Since it is relatively insensitive to the properties of their reducing or discharging products, various negative electrodes may be utilized in the batteries of the present light-emitting. Suitable negative electrodes for the cell of the present invention include, but are not limited to, negative electrodes containing a negative electrode active material selected from the group consisting of electroactive transition metal chalcogenides, electroactive conductive polymers, and electroactive sulfur containing materials. It is not limited. As used herein, the term "electroactive" belongs to the electrochemical properties of a material that occurs in the electrochemical reaction of charge or discharge in a current generating cell.

In one embodiment, the negative electrode of the cell of the invention contains an electroactive transition metal chalcogenide. Suitable transition metal chalcogenides are electroactive oxides, sulfides, and Mn, V, Cr, Ti, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta And selenides of transition metals selected from the group consisting of W, Re, Os, and Ir. The first transition metal chalcogenides are the electroactive oxides of vanadium and manganese.

In one embodiment, the negative electrode of the cell of the invention is an electroactive conductive polymer. Suitable conductive polymers include, but are not limited to, electroactive and electronically conductive polymers selected from the group consisting of polypyrroles, polyphenylenes, polythiofans, and polyacetylenes. Preferred conductive polymers are polypyrroles and polyacetylenes.

In one embodiment, the negative electrode of the cell of the invention contains an electroactive sulfur containing material. As used herein, the term “sulfur containing material” belongs to a negative electrode active material containing some form of elemental sulfur, and the electrochemical activity involves the breakdown or formation of sulfur-sulfur covalent bonds. The properties of the electroactive sulfur-containing material useful for the negative electrode of the battery of the present invention may be changed to various supports. The electroactive properties of elemental sulfur and other sulfur-containing materials are well known in the art and include the reversible formation of lithium oxide or lithium ion active materials during the discharge or cathodic reduction cycle of a battery.

In one embodiment, the electroactive sulfur-containing material of the negative electrode of the cell of the invention contains elemental sulfur. Examples of elemental sulfur as an electroactive cathode material are described in US Pat. No. 3,639,174 to Kegelman and US Pat. No. 5,523,179 to the state; 5,532,077; 5,582,623; And 5,682,201.

In one embodiment, the electroactive sulfur containing material is organic, ie it contains both sulfur and carbon atoms. In one embodiment, the exhibiting active sulfur-containing material is an organic material that contains a disulfide portion in its oxidation state. Examples of these organosulfide materials are described in Dejonghe and others, US Pat. Nos. 4,833,048 and 4,917,974; Visco and others 5,162,175 and 5,516,598; And materials of organosulfur as described in Oyama and elsewhere 5,324,599.

In one embodiment, the electroactive sulfur-containing material has the formula -S _m -in which the sulfur-containing cathode material is in its oxidation state, wherein m is an integer greater than or equal to 3, preferably m is an integer from 3 to 10, more preferred. M contains an electroactive sulfur containing material, containing a polysulfide quotient of an integer from 6 to 10. In a first embodiment, the electroactive sulfur containing material is a carbon-sulfur polymer. In one embodiment, the electroactive sulfur-containing material contains the polysulfide quotient of the formula -S _m- , wherein m contains an integer from 3 to 10, and at least one of their terminal sulfur atoms on the side group on the polymer backbone chain. Carbon-sulfur polymer material having their -S _m -groups covalently bonded by; Carbon-sulfur polymer material with their -S _m -groups incorporated into the polymer backbone chain by covalent bonding of their terminal yellows; And a carbon-sulfur polymer selected from the group of carbon-sulfur polymers, consisting of a carbon-sulfur polymer material having at least 75 weight percent of the carbon-sulfur polymer material. Examples of these carbon-sulfur polymer materials are described in US Pat. Nos. 5,529,860 to Scotime and elsewhere; 5,601,947; And US Pat. Appl. No. 08 / 995,122 to Co. Assignee, 5,609,702 and Gorcovenco, under "Electroactive, Energy Storage, Highly Crosslinked, Polysulfide-Containing Organic Polymers for Electrochemical Cells." Due to the presence of the multiple bond sulfur atoms, -S _m- , where m is an integer from 3 to 10, in these carbon-sulfur polymer materials, they correspond to disulfide bonds, -SS- alone, when discharged or reduced It has a significantly higher energy density or specific capacity than the material.

Anodes

Since the polyfunctional monomer of the non-aqueous electrolyte of the present invention exists as a kind that can be dissolved in the non-aqueous electrolyte, and this polyfunctional monomer having an oxidation or discharge product of the positive electrode active material and the positive electrode active material, and especially the polyfunctional vinyl ether Since the stability and reactivity of the monomers are generally similar to those of the solvents in the non-aqueous electrolyte, various positive electrodes may be utilized in the battery of the present invention.

Suitable positive electrode active materials for the positive electrode of the current-generating cell of the present invention include, but are not limited to, one or more metals or metal alloys or mixtures of one or more metals and one or more alloys. Selected from metals. Examples of positive electrode active materials suitable for the battery of the present invention include conductive polymers of alkali metal insertion and graphites and carbons of alkali metal insertion, such as polyacetylenes of lithium dope, polyphenylenes polypyrroles, etc. It is not limited to them. Particularly useful are positive electrode active materials containing lithium. Preferred positive electrode active materials for the positive electrode of the battery of the present invention are lithium metal, lithium-aluminum alloy, lithium-tin alloy, carbon of lithium insertion, and graphite of lithium insertion.

Current generation battery preparation method

Another aspect of the invention is a method of forming a current generating cell, the method comprising (i) provision of a negative electrode; (Ii) provision of the anode; And (iii) an intervention of the non-aqueous electrolyte between the positive electrode and the negative electrode, the electrolyte having viscosity and internal resistivity, (a) one or more solvents; (b) one or more ionic salts; And (c) a polyfunctional monomer containing at least two unsaturated aliphatic reactive shares per molecule, wherein the polyfunctional monomer can be dissolved in one or more solvents and rapidly polymerized when the electrolyte is heated to an onset temperature of at least 100 ° C. This increases the viscosity and internal specific resistance of the electrolyte.

How to increase the safety of current-generating cells

Another aspect of the invention is that (i) has viscosity and internal resistivity, and (a) one or more solvents; (b) one or more ionic salts; And (c) more than one unsaturated aliphatic reactivity share per molecule, which can be dissolved in one or more solvents, and rapidly polymerize when the electrolyte is heated to an onset temperature of 100 ° C. or higher, thereby increasing the viscosity and internal resistivity of the electrolyte. Preparation of a non-aqueous electrolyte containing a polyfunctional monomer to be added; And (ii) a step of charging the electrolyte into the current generating cell by interposing the electrolyte between the negative electrode and the positive electrode, wherein the safety of the current generating cell is increased. In one embodiment, in the rapid polymerization of the electrolyte at the initiation temperature, the viscosity and internal resistivity of the electrolyte increase to a level sufficient to safely terminate the current generating action of the cell.

Some embodiments of the invention are described in the following examples, which are provided by way of illustration and not limitation.

Example 1

Divinyl ethers ethylene glycol (DVEEG), diethylene glycol (DVEDEG), and triethylene glycol (DVETEG) were obtained from International Specialty Products, Wayne, NJ, dried over molecular sieves prior to use, and distilled under reduced pressure over sodium. The moisture content was 15 ppm or less. 1.0M solution of (LiN (SO ₂ CF ₃ ) ₂ (lithium imide, MN, St. Paul, 3M) available from dimethyl ether (available from TEGDME, LA, Zachary, Ferro Grant)) of tetraethylene glycol A non-aqueous liquid electrolyte was prepared In order to prepare the non-aqueous electrolyte of the present invention, divinyl ether was added to and mixed with this non-aqueous electrolyte, and four different electrolytes were prepared in which divinyl ether to TEGDME was prepared. A fourth solution having a weight ratio of DVEEG, DVEDEG and DVETEG with a 0.211: 1 weight ratio, respectively, and a weight ratio of 0.053: 1 of DVEEG to DVETEG and TEGDME (LiN (SO ₂ CF ₃ ) ₂ 1.0 M solution of TEGDME) The non-aqueous liquid electrolyte of was used as the control test electrolyte.

Elemental sulfur (WI, Milwaukee, available from Aldrich Chemical) 50% by weight, SAB-50 conductive carbon pigment (TX, trade name for sacetylene black available from Baytown, Chevron) 20% by weight, Al ₂ O ₃ (TX , Huston, trade mark for aluminum powders available from CONDEA Vista, 15% by weight of DISPAL 11N7-80), 15% by weight of polyethylene oxide (PEO) binder (PA, Warrington, Polyscience, Molecular Weight 200,000) Synthetic cathodes were prepared by suspending the dry component in an acetonitrile solution and mixing and grinding in a ball mill for 12 hours. The mixture was cast on both sides of 2.5 μm nickel foil (PA, Ivy Land, Teledyne-Rodney) by the doctor blade technique and dried at room temperature for 24 hours, followed by further drying at 60 ° C. for 1 hour under reduced pressure. . The resulting cathode thickness was about 35 μm per side, with an active material loading of about 1.8 mg / cm ² . Spiral AA cells were fabricated from the negative electrode, 4 mil lithium foil (NC, King Mountain, Cyprus-Foote) positive electrode, and 25 μm thick CELGARD 2500 separator (trademark for polyolefin separators available from NC, Charlotte, Hoechst Celanese). Assembled. The electrode jelly roll was inserted into the can, of stainless steel with a single casting hole on the can base. The cell holes were designed to release the internal pressure of the cell when the internal pressure ranged from 600 to 800 psi. Five sets of three cells using a reduced pressure backfill technique, one set of three AA cells for each of four different liquid electrolyte solutions containing divinyl ether monomers, and one set of three AA cells for the control electrolyte solution Was filled with a liquid electrolyte solution.

Each of the four sets of AA cells with the divinyl ether in question showed good thermal stability when stored, discharged, and charged at temperatures up to 60 ° C. Four repeated discharge charge cycles at a discharge current of 450 mA and taper charge at 275 mA until a voltage of 2.4 V have been reached to continue charging for three more hours at 2.4 V, with diethylene glycol of divinyl ether. AA cells showed poor capacity retention in cycling. Although the specific capacity of AA cells containing DVEDEG had a good specific capacity of 1099 mAh average per gram of elemental sulfur donated to the cathode at the first discharge, they showed a large loss in specific capacity by the end of the fourth cycle. No further cycling or safety testing of the cell was made. The other three sets of AA cells containing divinyl ether showed good specific capacity at the first discharge, as shown in Table 1, and had good specific capacity at the end of the fourth cycle. These three sets of AA cells were then cycled for at least 10 cycles at a discharge current of 275 mA to reach 2.4 V with voltage controlled charging at 250 mA. The specific capacity of the three sets of AA cells was still good after a total of 14 cycles, as shown in Table 1, and all were 130 ° C. except for one cell with triethylene glycol (DVETEG) of divinyl ether. Was subjected to the hot box test for 60 minutes at. The hot box was an oven closed with thermocouples to monitor the temperature of the oven and of the cells in the holes over the test time. One cell with DVETEG, not used in the hot box test, was cycled for an additional 20 cycles under the same discharge and charge conditions for the first four cycles. This cell showed a stable specific capacity from its 15th to 34th cycles.

The 60 minute test at 130 ° C. showed a difference among three sets of AA cells with divinyl ether donated in liquid electrolyte. Both cells with DVETEG were on fire after 13 to 15 minutes of testing and failed the safety test. The puncture was not observed for the three cells with low weight ratio DVEEG to TEGDME solvent and passed the safety test without cell temperature exceeding 130 ° C in the oven. Testing of all three sets of AA cells after completion of the hot box test showed that for all cells the liquid electrolyte turned to gel. In contrast, all cells with TEGDME-controlled electrolytes failed the hot box safety test by puncturing with fire.

Test data for batteries with electrolytes containing divinyl ether Seriousness No. Divinyl ether Weight ratio of divinyl ether to EGDME Primary discharge mAh / g 14th discharge nAh / g 130 degrees Celsius hot box test One DVEEG 0.211 910 516 Hole 2 DVEEG 0.211 939 642 Hole 3 DVEEG 0.211 933 598 Hole 4 DVEDEG 0.211 1070 no data Not tested 5 DVEDEG 0.211 1128 no data Not tested 6 DVEDEG 0.211 1100 no data Not tested 7 DVETEG 0.211 974 661 Failure, fire 8 DVETEG 0.211 1002 699 Failure, fire 9 DVETEG 0.211 1042 750 Not tested 10 DVEEG 0.053 980 519 No hole 11 DVEEG 0.053 904 498 No hole 12 DVEEG 0.053 988 538 No hole

Polymerization of divinyl ether is known to be exothermic. Depending on the nature and concentration of the divinyl ether, the exothermic heat of the polymerization may be high and rapid enough to increase the cell temperature before the cell is safely controlled or terminated, causing failure of the hot box safety test. A decrease of 0.053; 1 from 0.211; 1 in weight ratio to TEGDME solvent in the amount of DVEEG was sufficient to stabilize the cell during the hot box safety test and to close the cell without increasing the temperature of the hot box above 130 ° C. Although it plays a great role in the safe operation of liquid electrolytes, it is important to know that the concentration of divinyl ether (DVEEG) had only a valueless effect on electrochemical performance. These results indicate that the properties of non-aqueous electrolytes with multifunctional unsaturated aliphatic reactive monomers, such as divinyl ether monomers, may be tuned to provide an effective combination of electrochemical performance and safety.

The ionic conductivity of the electrolyte with DVEEG (5.3%) was 3.0 mS / cm in the liquid state. The ion conductivity was reduced to 1.3 mS / cm in gel form.

Example 2

As a control electrolyte, LiSO ₃ CF ₃ (MN, St. Chem.) Of 50 vol% of 1,2-dimethoxyethane (DME), 45 vol% of 1.3-dioxolane (1,3-DOL) and 5 vol% of ortho-xylene. A non-aqueous electrolyte of lithium triflate) 1.3 M solution, available from Paul, 3M, was prepared. Two electrolytes in which 5 volume% DME (group 1) or 5 volume% 1,3-DOL (group 2) were replaced with triethylene glycol (DVETEG) of divinyl ether were prepared by standard methods. The electrolyte composition and control of each group is summarized in Table 2.

Electrolyte Composition Battery Group DME Volume% 1,3-DOL Volume% O-XYL Volume% DVETEG Volume% Group 1 50 45 5 0 Group 1 45 45 5 5 Group 2 50 40 5 5

60% elemental sulfur, 10% conductive pigments (trademarks of carbon pigments available from PRINTEX XE-2, OH, Akron, Degussa), 20% inert carbon nanofibers (PYROGRAF-III, OH, Cedarville, Applied Sciences Commercially available carbon nanofibers), 5% SiO ₂ (trademark of AEROSIL 380, OH, Akron, silica available from Degussa), 5% polytetrafluoroethylene binder (TEFLON, DE, Wilmington, Synthetic cathode having a composition (based on dry weight) of PTFE polymer available from DuPont, was prepared by standard paste method using isopropanol as a dispersion medium, and 175 µm aluminum EXMET (CT, Naugatuck) , A trademark of a metal grid current collector which can be dumped from EXMET. The negative electrode was dried at 60 DEG C for 1 hour under reduced pressure. The resulting dry cathode had a total thickness in the range of 200 μm with an active cathode material loading density of 3.0 mg / cm ² . Spiral AA cells were prepared from synthetic sulfur anodes, 25 μm E25 SETELA separators (trademark of polyolefin separators available from Tonen Chemical, Tokyo, Japan and also available from NY, Pittsford, Films Division, Mobil Chemical), and 100 μm Li foil Assembled with positive electrode. An electrode jelly roll was inserted into a stainless can, as described in Example 1. The cells were charged by either the control liquid electrolyte or the electrolyte containing 5% by volume of DVETEG by the Baumum bag peeling technique.

The cells were cycled 5 cycles at 100 and 165 mA charge discharge rates, respectively. The specific discharge capacity of one sheet showing each electrolyte formalization and control test is shown in the figure. No significant difference was observed in cycling behavior and specific capacity between the cells with the control test electrolyte and those with the electrolyte containing DVETEG. At the end of the fifth cycle the cells were changed and a 130 ° C., 60 minute hot box safety test was performed. The results of the safety test are summarized in Table 3.

130 ℃, 60 minutes, hot box safety test result Battery group Number of batteries Pass failure Control 0 2 Group 1 2 0 Group 2 2 0

Dojo test The batteries with electrolyte failed holes or safety tests. Test data indicating the dependence of the oven, case temperature, and cell voltage versus time for one cell in the control test group are shown in FIG. 2. At about 47 minutes, the spikes show holes in the cell. The cells of groups 1 and 2 with electrolyte containing 5% by volume of DVTEG passed the safety test without holes. Test data showing the dependence of the oven, case temperature and cell voltage versus time for one cell in group 1 are shown in FIG. 3.

Gelation of the electrolyte was observed to occur when the cell was open. At 130 ° C., the polymerization of the electrolyte that will form the gel should occur within about 10 minutes in relation to the hot box test. At 100 ° C., the initiation of the polymerization of the electrolyte donated with the divinyl ester typically requires about 15 to 20 minutes. In the presence of an effective initiator, the speed of the galvanization process is increased, typically occurring within 5 to 30 seconds, for example at 130 ° C.

The conductivity of these liquid electrolytes with the divinyl ether in question was observed to be in the range of 8-12 mS / cm before polymerization and in the range of 1-3 mS / cm after polymerization or gelation.

Example 3

A non-aqueous control electrolyte solution of 95 vol% DME and 5 vol% O-XYL 1.3 M lithium imide was prepared. Two non-aqueous electrolyte solutions were also prepared in which 5 volume% (group 3) or 11 volume% DME was replaced with DVETEG.

60% by weight of elemental sulfur, 20% by weight of inert carbon nanofibers (PYROGRAF-III), 10% by weight of PRINTEXE-2 carbon pigments, 5% by weight of SiO ₂ (MA, Billerica, Cabot) W spiral spiral cells of synthetic paste anodes having the composition of a commercially available silica), and 5% by weight of a TEFLON binder, a thickness of 250 μm and an active cathode material loading density of 3.3 mg / cm ² , are described in Example 2. As prepared. Four cells for each group and control test were filled with electrolyte by back-up back filling.

The cells were cycled for 10 cycles at a discharge rate of 165 mA and a charge rate of 75 mA before the 130 ° C. hot box safety test. The test results are summarized in Table 4.

Electrolyte Composition Battery group DME Volume% O-xylene volume% DVETEG volume% 10th cycle total capacity mAh 130 ℃ Hot Box Safety Test: Number of Batteries Pass failure Control 95 5 0 753, 728,670, 673 One 3 Group 3 90 5 5 654, 630, 608, 609 3 One Group 4 84 5 11 529, 639,623, 550 One 3

Control cells showed a 75% failure rate, while those with an electrolyte with 5% DVETEG had a pass rate of 75%, indicating a safety improvement for batteries with electrolytes containing divinyl ether. Four cells of electrolyte with 11% DVETEG had a 75% failure rate as observed for the control cell. The high failure rate of batteries containing a large proportion of DVETEG may be explained by the exothermic effect of the polymerization of divinyl ether.

Example 4

A non-aqueous liquid electrolyte of 1.15 M solutions of lithium imide with DVETEG and lithium imide without DVETEG was prepared as shown in Table 5 as a control. Spiral AA cells of the negative electrode type of Example 3 (active material loading 3.2 mg / cm ² ) were assembled to fill the electrolyte as described in Example 3. The cells were cycled 10 cycles at a discharge rate of 165 mA and a charge rate of 75 mA before a 60 minute 130 ° C. hot box safety test.

Electrolyte Composition battery group DME volume% TEGDME volume% O-XYL volume% Sulfolane Volume% 1,3-DOL Volume% DVETEG volume% 10th cycle total capacity mAh Control 20 20 5 5 50 0 760, 780 Group 5 20 20 5 5 45 5 610, 620 Group 6 20 15 5 5 50 5 610, 550 Group 7 20 20 5 0 50 5 570

Cells containing divinyl ether in the electrolyte passed the hot box safety test at 130 ° C. for 60 minutes, as shown in Table 6, whereas all control cells failed.

130 ℃, 60 minutes, hot box safety test result Battery group Number of batteries pass failure Control 0 2 Group 5 2 0 Group 6 2 0 Group 7 One 0

Example 5

1.3 M solution of lithium imide with and without lithium imide with a mixture of three polyfunctional monomers which is a divinyl ether / diallyl ether of DVETEG / 1,4-cyclohexanedimethanol ether in a volume ratio of 3: 1: 1 The non-aqueous liquid electrolytes of were prepared as shown in Table 7.

Electrolyte Composition battery group DME volume% 1,3-DOL Volume% O-XYL volume% combination Monomer additive volume% 5th cycle total capacity mAh Control 45 50 5 0 703, 711 Group 8 45 45 5 5 724, 670 Group 9 40 50 5 5 670, 684 Group 10 40 45 5 10 No test

Spiral AA cells were manufactured by Gorcobenco and other common assignees under 65 weight percent carbon-sulfur polymer ("electroactive, energy storage, high cross-linked, polysulfide-containing organic polymer for electrochemical cells"). Prepared by the process described in Example 2 of US patent application SN 08 / 995,122), 10 wt% conductive carbon pigment (PRINTEX XE-2), 20 wt% PYROGRAF-III carbon nanofiber, 5 wt% PEO ( Molecular weight 200,000, available from PA, Warrington, Polysciences), and a synthetic paste negative electrode composition of 5% by weight of TEFLON polymer prepared by the method described in Example 2, assembled as described in Example 2. The loading of carbon-sulfur polymer was 3.6 mg / cm ² .

The cells were filled with an electrolyte as described in Example 3. The cells correspond to an average of 165 mADC at a rate of 100 mA discharge and charge up to 1.25 and 3.0 V shutoff (150% overcharge) for the first cycle and 150% overcharge (1.25 and 3.0 V shutoff) for subsequent cycles. Circulated under GSM pulse discharge. After the fifth cycle, the cells were tested for 130 minutes hot box safety for 60 minutes. The results are shown in Table 8.

130 ℃, 60 minutes, hot box safety test result Battery group Number of batteries pass failure Control One One Group 8 2 0 Group 8 2 0 Group 10 One 0

Cells with a mixture of three different polyfunctional monomers exhibited safe operation, whereas control cells exhibited lower safe operation.

Example 6

A non-aqueous liquid electrolyte was prepared in a 0.75 M solution of lithium imide of 50 vol% 1,3-DOL, 45 vol% DME, and 5 vol% divinyl ether of triethylene glycol (DVETEG). As a control test, a non-aqueous liquid electrolyte of 0.75 M solution of 50 vol% 1,3-DOL and 50 vol% DME lithium imide was used.

Footnote type printing cells were prepared by the method described in Example 1 using isopropanol as a solvent and obtained from an 18 μm conductive carbon coated aluminum foil (Product No. 60303. MA, South Hadley, Rexam Graphics) as a current collector. Composite cathode, composed of 75% elemental sulfur, 20% conductive carbon pigment (PRINTEX XE-2) and 5% inert carbon nanofiber (PYROGRAF-III) cast on both sides And a 2 mil lithium foil positive electrode and an E25 SETELA or CELGARD separator. The cells were filled with a DVETEG containing liquid electrolyte or control test electrolyte by the reduced pressure backfill technique. All materials were circulated between 4 and 19 cycles at a charge rate of 100, 150, 200 or 300 mA and at a rate of 150, 200, 250, 350 or 500 mA. The capacity of both test and control test cells ranged from 250 to 1200 mAh in the final cycle before safety testing. After the final charge cycle the cells were tested for 130 minutes hot box safety for 60 minutes.

Comparative cells with control electrolytes showed 75% failure by blasting with fire, whereas cells with liquid electrolytes containing 5% triethylene glycol of divinyl ether showed a pass rate of 88%, resulting in a polyfunctional monomer. It shows an excellent safe operation of the non-aqueous electrolyte containing.

Example 7

Two cells as described in Example 6 were cycled for 25 cycles. Then, the batteries were left at a temperature of 55 ° C. for 6 days in a charged state. After this pause, the cycles of the cells were restarted. The specific capacity of the cells returned to their pre-stop value after 5 cycles. Control cells showed exactly the same response. The results indicate that there was no adverse effect on cell performance when stored at 55 ° C. for 6 days for batteries with or without a non-aqueous electrolyte containing a polyfunctional monomer.

The present invention provides a composition comprising (a) one or more solvents; (b) one or more ionic salts; And (c) a non-aqueous electrolyte containing a polyfunctional monomer containing at least two unsaturated aliphatic reactive shares per molecule, the polyfunctional monomer being soluble in one or more solvents and having an onset temperature of at least 100 ° C. The polymer is rapidly polymerized when the electrolyte is heated to increase the viscosity and internal resistivity of the electrolyte. When incorporated into a non-aqueous electrolyte, the polyfunctional reactive monomer improves the safety of the current generating cell by rapidly polymerizing at elevated temperatures to increase the viscosity and internal resistivity of the electrolyte.

Having described the invention in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (84)

(Iii) a cathode; (Ii) an anode; And (Iii) a nonaqueous electrolyte placed between the cathode and the anode, And the electrolyte has viscosity and internal resistivity, (a) one or more solvents; (b) one or more ionic salts; And (c) a polyfunctional monomer containing at least two unsaturated aliphatic reactive shares per molecule, the polyfunctional monomer being capable of dissolving in one or more solvents and rapidly when the electrolyte is heated to an onset temperature of at least 100 ° C. By polymerizing, to increase the viscosity and the internal resistivity of the electrolyte solution, Current generating cell. The method of claim 1, In the rapid polymerization of the electrolyte at the start temperature, the viscosity and internal resistivity of the electrolyte increase to a level sufficient to safely terminate the current generating action of the battery. The method of claim 1, The reactive share is Vinyl (CH ₂ = CH-), Allyl (CH ₂ = CH-CH _2- ), Vinyl ether (CH ₂ = CH-O-), Allyl ether (CH ₂ = CH-CH ₂ -O-), Allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), Allyl amine (CH ₂ = CH-CH ₂ -NH-), Acrylyl (CH ₂ = CH-C (O)-), Acrylate (CH ₂ = CH-C (O) -O-), Acrylamide (CH ₂ = CH-C (O) -NH-), Methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), Methacrylate (CH ₂ ═C (CH ₃ ) —C (O) —O—), and Crotoxyl (CH ₃ -CH = C (CH ₃ ) -C (O)-), A current generating battery selected from the group consisting of. The method of claim 1, The polyfunctional monomer is a current-generation battery is a polyfunctional vinyl ether monomer. The method of claim 1, Wherein said multifunctional monomer is a polyfunctional vinyl ether selected from the group consisting of divinyl ether monomers, trivinyl ether monomers, and tetravinyl ether monomers. The method of claim 1, The polyfunctional monomer is a divinyl ether monomer current generating battery. The method of claim 1, The polyfunctional monomer is Ethylene glycol of divinyl ether, Diethylene glycol of divinyl ether, Triethylene glycol of divinyl ether, Tetraethylene glycol of divinyl ether, 1,4-butanediol of divinyl ether, and 1,4-cyclohexanedimethanol of divinyl ether A current generating cell which is divinyl ether selected from the group consisting of. The method of claim 1, Wherein said electrolyte is selected from the group consisting of liquid electrolytes, gel polymer electrolytes, and solid polymer electrolytes. The method of claim 1, And the electrolyte is a liquid electrolyte. The method of claim 1, The at least one solvent is a current containing a solvent selected from the group consisting of N-methyl acetamide, acetonitrile, organic carbonate, sulfolane, sulfone, N-alkyl pyrrolidone, dioxolane, glim, siloxane and xylene Produce battery. The method of claim 1, Wherein said at least one ion salt contains a lithium salt. The method of claim 11, The lithium salt is LiClO ₄ , LiAsF ₆ , LiSO ₃ CF ₃ , LiSO ₃ CH ₃ , LiBr, LiI, LiSNC, LiBF ₄ LiB (phenyl) ₄ , LiPF ₆ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , And A current generating battery selected from the group consisting of. The method of claim 1, Wherein the weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of said one or more solvents is in the range of 0.01: 1 to 0.25: 1. The method of claim 1, Wherein the weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of said one or more solvents is in the range of 0.02: 1 to 0.15: 1. The method of claim 1, And a weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of said one or more solvents is in the range of 0.02: 1 to 0.1: 1. The method of claim 1, The electrolyte further contains a monofunctional monomer, having one unsaturated aliphatic reactive quotient per molecule, soluble in the one or more solvents, and reacting rapidly with the polyfunctional monomer when the electrolyte is heated to the initiation temperature; Current generating cells. The method of claim 16, Wherein said monofunctional monomer is a monofunctional monomer selected from the group consisting of vinyl ethers and allyl ethers. The method of claim 16, The monofunctional monomer is 1-butanol of vinyl ether, 2-ethylhexanol of vinyl ether, and Cyclohexanol of vinyl ether, A current generating cell which is a monofunctional vinyl ether selected from the group consisting of. The method of claim 16, And a weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of one or more solvents and donor polyfunctional monomers is in the range of 0.005: 1 to 0.2: 1. The method of claim 16, And a weight ratio of the combined total weight of donor monofunctional monomers to the combined total weight of one or more solvents and donor polyfunctional monomers is in the range of 0.01: 1 to 0.1: 1. The method of claim 1, And the electrolyte further contains a polymerization initiator such that the initiator increases the rate of polymerization of the multifunctional monomer when the electrolyte is heated to the initiation temperature. The method of claim 21, Wherein said initiator comprises a cationic polymerization initiator. The method of claim 21, The initiator is a current generating battery containing lithium ions. The method of claim 1, And the electrolyte further contains a polymerization inhibitor such that the inhibitor reduces the rate of polymerization of the multifunctional monomer when the electrolyte is heated to the initiation temperature. The method of claim 24, The inhibitor is a tertiary amine. The method of claim 1, And the negative electrode comprises an electroactive sulfur-containing material containing elemental sulfur. The method of claim 1, And the negative electrode contains an electroactive sulfur-containing material containing a polysulfide quotient of -S _m- , wherein m is from 3 to 10 in its oxidation state. The method of claim 27, Wherein said electroactive sulfur-containing material comprises a carbon-sulfur polymer. The method of claim 28, Wherein the polysulfide quotient, -S _m- , m is an integer from 6 to 10; The method of claim 28, Wherein said carbon-sulfur polymer has a polymer backbone chain and is covalently bonded by the polysulfide quotient, -S _m- , one or both of its terminal sulfur atoms on this side group. The method of claim 28, And wherein the carbon-sulfur polymer has a polymer backbone chain and the polysulfide quotient, -S _m- , is incorporated into the polymer backbone chain by covalent bonds to both of its terminal sulfur atoms. The method of claim 28, Wherein said carbon-sulfur polymer contains at least 75 weight percent of sulfur. The method of claim 1, And the negative electrode contains an electroactive sulfur-containing material containing a disulfide group in its oxidized state. The method of claim 1, And the negative electrode comprises an electroactive transition metal chalcogenide. The method of claim 1, The negative electrode is a current generating battery containing an electroactive conductive polymer. The method of claim 1, Wherein said positive electrode contains at least one positive electrode active material selected from the group consisting of lithium metal, lithium-aluminum alloy, lithium-tin alloy, lithium intercalated carbon, and lithium intercalated graphite. The method of claim 1, The multifunctional monomer is a current generating battery that does not significantly polymerize for more than 36 hours at a temperature of 60 ℃. The method of claim 1, The multifunctional monomer is a current generating battery that does not significantly polymerize for more than 36 hours at a temperature of 80 ℃. The method of claim 1, The multifunctional monomer is a current generating battery that does not rapidly polymerize at a temperature of 100 ℃ or less. The method of claim 1, The multifunctional monomer is a current generating battery that does not rapidly polymerize at a temperature of 110 ℃ or less. The method of claim 1, The multifunctional monomer is a current generating battery that does not rapidly polymerize at a temperature of 120 ℃ or less. The method of claim 1, The multifunctional monomer is a current generating battery that does not rapidly polymerize at a temperature of 130 ℃ or less. The method of claim 1, The multifunctional monomer is a current generating battery that does not rapidly polymerize at a temperature of 150 ℃ or less. The method of claim 1, The multifunctional monomer is a current generating battery that does not rapidly polymerize at a temperature of 170 ℃ or less. The method of claim 1, The electrolyte further comprises a solid porous separator. The method of claim 45, Wherein said separator is a porous polyolefin separator. The method of claim 45, And the separator comprises a microporous pseudo bemate layer. The method of claim 45, The separator is a current generating battery that does not dissolve at a temperature of 100 ° C. or more, which is the lowest temperature at which polymerization of the multifunctional monomer occurs rapidly to increase the viscosity and internal resistivity of an acid group electrolyte. A non-aqueous electrolyte used in a current generating battery, wherein the electrolyte has viscosity and internal resistivity, and the electrolyte (Iii) one or more solvents; (Ii) one or more ionic salts; And (Iii) each molecule contains two or more unsaturated aliphatic reactivity shares, which can be dissolved in the one or more solvents, and rapidly polymerizes when the electrolyte is heated to an onset temperature of 100 ° C. or higher, thereby providing the viscosity and internal intrinsic of the electrolyte. Polyfunctional monomer to increase resistance, A non-aqueous electrolyte consisting of. The method of claim 49, The reactive share is Vinyl (CH ₂ = CH-), Allyl (CH ₂ = CH-CH _2- ), Vinyl ether (CH ₂ = CH-O-), Allyl ether (CH ₂ = CH-CH ₂ -O-), Allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), Allyl amine (CH ₂ = CH-CH ₂ -NH-), Acrylyl (CH ₂ = CH-C (O)-), Acrylate (CH ₂ = CH-C (O) -O-), Acrylamide (CH ₂ = CH-C (O) -NH-), Methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), Methacrylate (CH ₂ ═C (CH ₃ ) —C (O) —O—), and Crotoxyl (CH ₃ -CH = C (CH ₃ ) -C (O)-), A current generating battery selected from the group consisting of. The method of claim 49, The polyfunctional monomer is an electrolyte that is a multifunctional vinyl ether monomer. The method of claim 49, Wherein said polyfunctional monomer is a polyfunctional vinyl ether monomer selected from the group consisting of divinyl ether monomers, trivinyl ether monomers, and tetravinyl ether monomers. The method of claim 49, The polyfunctional monomer is a divinyl ether monomer. The method of claim 49, The polyfunctional monomer is Ethylene glycol of divinyl ether, Diethylene glycol of divinyl ether, Triethylene glycol of divinyl ether, Tetraethylene glycol of divinyl ether, 1,4-butanediol of divinyl ether, and 1,4-cyclohexanedimethanol of divinyl ether, An electrolyte which is divinyl ether selected from the group consisting of. The method of claim 49, The electrolyte is selected from the group consisting of liquid electrolytes, gel polymer electrolytes, and solid polymer electrolytes. The method of claim 49, The electrolyte is a liquid electrolyte. The method of claim 49, The at least one solvent is an electrolyte containing a solvent selected from the group consisting of N-methyl acetamide, acetonitrile, organic carbonate, sulfolane, sulfone, N-alkyl pyrrolidone, dioxolane, glim, siloxane and xylene . The method of claim 49, Wherein said at least one ionic salt contains a lithium salt. The method of claim 58, The lithium salt is LiClO ₄ , LiAsF ₆ , LiSO ₃ CF ₃ , LiSO ₃ CH ₃ , LiBr, LiI, LiSNC, LiBF ₄ LiB (phenyl) ₄ , LiPF ₆ , LiC (SO ₂ CF ₃ ) ₃ , LiN (SO ₂ CF ₃ ) ₂ , And An electrolyte selected from the group consisting of. The method of claim 49, An electrolyte wherein the weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of said one or more solvents is in the range of 0.01: 1 to 0.25: 1. The method of claim 49, An electrolyte wherein the weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of said one or more solvents is in the range of 0.02: 1 to 0.15: 1. The method of claim 49, The electrolyte wherein the weight ratio of the combined total weight of donor polyfunctional monomers to the combined total weight of the one or more solvents is in the range of 0.02: 1 to 0.1: 1. The method of claim 49, The electrolyte further contains a monofunctional monomer, having one unsaturated aliphatic reactivity share per molecule, soluble in the one or more solvents, and reacting rapidly with the multifunctional monomer when the electrolyte is heated to the initiation temperature; Electrolyte. The method of claim 63, wherein The monofunctional monomer is an electrolyte selected from the group consisting of vinyl ethers and allyl ethers. The method of claim 63, wherein The monofunctional monomer is 1-butanol of vinyl ether, 2-ethylhexanol of vinyl ether, and Cyclohexanol of vinyl ether, An electrolyte which is a vinyl ether selected from the group consisting of. The method of claim 49, And the electrolyte further contains a polymerization initiator such that the initiator increases the rate of polymerization of the multifunctional monomer when the electrolyte is heated to the initiation temperature. The method of claim 66, wherein The initiator is an electrolyte containing a cationic polymerization initiator. The method of claim 66, wherein The initiator is an electrolyte containing lithium ions. The method of claim 49, The electrolyte further contains a polymerization inhibitor such that the inhibitor reduces the rate of polymerization of the multifunctional monomer when the electrolyte is heated to the initiation temperature. The method of claim 69, The inhibitor is a tertiary amine. The method of claim 49, The electrolyte further comprises a solid porous separator. The method of claim 71 wherein The separator is an electrolyte of a porous polyolefin separator. The method of claim 71 wherein Said separator containing a microporous pseudo bemate layer. A method of forming a current generating cell, the method of (Iii) providing a cathode; (Ii) providing an anode; (Iii) inserting a nonaqueous electrolyte between the positive electrode and the negative electrode Consisting of steps, the electrolyte has viscosity and internal resistivity, (a) one or more solvents; (b) one or more ionic salts; And (c) contains more than one unsaturated aliphatic reactive shares per molecule and is soluble in the one or more solvents and rapidly polymerizes when the electrolyte is heated to an onset temperature of at least 100 ° C., thereby reducing the viscosity and internal resistivity of the electrolyte. A current generating battery forming method containing a multifunctional monomer to increase. The method of claim 74, wherein In the rapid polymerization of the electrolyte at the initiation temperature, the viscosity and internal resistivity of the electrolyte increase to a level sufficient to safely terminate the current generating action of the battery. The method of claim 74, wherein The reactive shares Vinyl (CH ₂ = CH-), Allyl (CH ₂ = CH-CH _2- ), Vinyl ether (CH ₂ = CH-O-), Allyl ether (CH ₂ = CH-CH ₂ -O-), Allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), Allyl amine (CH ₂ = CH-CH ₂ -NH-), Acrylyl (CH ₂ = CH-C (O)-), Acrylate (CH ₂ = CH-C (O) -O-), Acrylamide (CH ₂ = CH-C (O) -NH-), Methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), Methacrylate (CH ₂ ═C (CH ₃ ) —C (O) —O—), and Crotoxyl (CH ₃ -CH = C (CH ₃ ) -C (O)-), A current generating battery forming method selected from the group consisting of. The method of claim 74, wherein Wherein said polyfunctional monomers are polyfunctional vinyl ether monomers. A method for preparing a non-aqueous electrolytic cell for use in a current generating battery, wherein the electrolyte has viscosity and internal resistivity, (a) a solution of one or more solvents; Two or more ionic salts; And each molecule contains two or more unsaturated aliphatic reactive shares, is soluble in the one or more solvents, and rapidly polymerizes when the electrolyte is heated to an onset temperature of 100 ° C. or more, thereby increasing the viscosity and internal resistivity of the electrolyte. To prepare a polyfunctional monomer; (b) optionally incorporating the solution with a solid porous separator, an ion conductive polymer, and other materials selected from the group consisting of multifunctional monomers having one unsaturated aliphatic reactive share per molecule, A non-aqueous electrolyte preparation method comprising the steps. The method of claim 78, The reactive shares Vinyl (CH ₂ = CH-), Allyl (CH ₂ = CH-CH _2- ), Vinyl ether (CH ₂ = CH-O-), Allyl ether (CH ₂ = CH-CH ₂ -O-), Allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), Allyl amine (CH ₂ = CH-CH ₂ -NH-), Acrylyl (CH ₂ = CH-C (O)-), Acrylate (CH ₂ = CH-C (O) -O-), Acrylamide (CH ₂ = CH-C (O) -NH-), Methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), Methacrylate (CH ₂ ═C (CH ₃ ) —C (O) —O—), and Crotoxyl (CH ₃ -CH = C (CH ₃ ) -C (O)-), A non-aqueous electrolyte preparation method selected from the group consisting of: The method of claim 78, And the polyfunctional monomer is a polyfunctional vinyl ether monomer. To increase the safety of the current generating battery, (Iii) the electrolyte has viscosity and internal resistivity, (a) one or more solvents; (b) one or more ionic salts; And (c) contains more than one unsaturated aliphatic reactive shares per molecule and contains a polyfunctional monomer which rapidly polymerizes when the electrolyte is heated to an onset temperature of at least 100 ° C., thereby increasing the viscosity and internal resistivity of the electrolyte, Preparing a non-aqueous electrolyte; (Ii) integrating the electrolyte into the current generating cell by placing the electrolyte between a cathode and an anode; The method consists of steps. 82. The method of claim 81 wherein In rapid polymerization of said electrolyte at said initiation temperature, said viscosity and internal resistivity of said electrolyte increase to a level sufficient to safely terminate the current generating action of said battery. 82. The method of claim 81 wherein The reactive shares Vinyl (CH ₂ = CH-), Allyl (CH ₂ = CH-CH _2- ), Vinyl ether (CH ₂ = CH-O-), Allyl ether (CH ₂ = CH-CH ₂ -O-), Allyl ester (CH ₂ = CH-CH ₂ -C (O) -O-), Allyl amine (CH ₂ = CH-CH ₂ -NH-), Acrylyl (CH ₂ = CH-C (O)-), Acrylate (CH ₂ = CH-C (O) -O-), Acrylamide (CH ₂ = CH-C (O) -NH-), Methacrylyl (CH ₂ = C (CH ₃ ) -C (O)-), Methacrylate (CH ₂ ═C (CH ₃ ) —C (O) —O—), and Crotoxyl (CH ₃ -CH = C (CH ₃ ) -C (O)-), A method for increasing safety of current generating battery selected from the group consisting of: 82. The method of claim 81 wherein Wherein said polyfunctional monomer is a polyfunctional vinyl ether monomer.